(1) Field of the Invention
The present invention relates to a diaphragm spring device used in a friction clutch for automobiles and others.
(2) Description of the Prior Art
It is well known that a diaphragm spring for such a clutch is employed to push a pressure plate onto a friction facing or lining and is connected to a clutch operating mechanism to control the above pushing operation. The diaphragm spring has a radially outer portion of a continuously annular shape and a radially inner portion which is divided into radial tongues. Generally, the diaphragm spring is seated at the radially outer portion of the pressure plate, is supported at the radially middle portion by a clutch cover by means of fulcrum means and is engaged at the radially inner end with the operating mechanism, i.e., a release bearing.
As stated above, the diaphragm spring has function as a release lever, in addition to the function as the spring itself. At present, in order to increase a leverage of the release lever, i.e., the diaphragm spring, manufactures attempt to increase the length of the tongues. However, the long tongues may cause error in the axial positions of the inner ends thereof in the manufacturing process. Thus, in the conventional arrangement, in which the release bearing merely contact the long tongues, deviation is caused in the relationship between a travel of the release bearing and a deflection of the diaphragm spring, and thus it is difficult to precisely set intended release characteristics. Further, there may be caused judder in a clutch cover assembly including the diaphragm spring.
Prior arts will be more specifically described below in connection with the present invention.
The present invention has a purpose to prevent deviation in an axial position of tongues by associating positioning members or components with the ends of the tongues. An idea of associating certain members with the ends of the tongues is disclosed in the Japanese Laid-Open Patent Publication No. 62-37522. However, in a clutch disclosed in this publication, a fulcrum of the diaphragm spring is located radially outside a point of action, i.e., the point connected to a pressure plate, so that the release bearing is adapted to pull the ends of the tongues rearward for disengaging the clutch, which is contrary to the case in the present invention. Further, at the vicinity of the tongues, there are provided an annular member, which requires high precision and is of a complicated shape, a wire ring, a spring and others, resulting in a complicated structure.
That is; the above publication has disclosed the structures in the clutch of a pull type, in which the tongues are pulled rearward to release the clutch, for connecting the release bearing to the diaphragm spring while permitting disassembly thereof, and contrary to the invention, has not proposed an idea for dissolving the above stated problems by simple structures in the clutch of a push type in which the tongues are pushed to disengage the clutch.
Accordingly it is an object of the invention to provide an improved device, overcoming the above-noted disadvantage.